How do I add a custom favicon (PNG) to a Figma Make project website?

I'm building a web app in Figma Make and trying to set a custom favicon. I've tried two approaches so far:

1. Adding <link rel="icon"> tags directly to index.html — but a favicon diagnostic tool confirms these tags aren't appearing in the served HTML, suggesting Figma Make generates its own HTML wrapper that overrides index.html.
2. Placing favicon files in the /public folder — the diagnostic tool confirms /public files ARE served (it found favicon.ico at the root), but I can only create text-based files through the Figma Make code editor, not upload binary .png or .ico files.

Is there a supported way to upload a custom binary favicon (PNG or ICO) to a Figma Make project? Or is there a way to make custom <link> tags in index.html pass through to the served HTML?

Any workarounds welcome. Thanks!